Staging devices



July 17, 1962 L. A. ENGEMAN ETAL 391 4352 STAGING DEVICES Filed March 30, 1959 2 Sheets-Sheet 1 INVENTORS Leonard A. [mama/1 flo- J 6 W ATTORNEY y 1962 L. A. ENGEMAN ETAL 3,044,352

STAGING DEVICES Filed March 30, 1959 2 s t g 2 II "III II III ma F7 INVENTOR-S J g. 5 Leonard A. Enaeman BY Kennef/z a Paper?- ZM 5W ATTORNEY 3,44,352 Patented July 17, 1962 Filed Mar. 30, 1959, Ser. No. 802,750 2 Claims. on. 88-24) This invention relates to inspection fixtures generally and more specifically to staging devices for use with projection gaging equipment.

The exigencies of modern manufacturing demand rapid inspection of many articles. To meet this need, many techniques such as projection gaging have been developed. The present invention is particularly useful in this method of inspection, as applied to dimensional gaging of insulating spacers used in the manufacture of electron discharge devices.

The insulating spacers or micas employed as supports in electron discharge devices are generally circular discs having a plurality of spaced perforations placed in a par- \icul-ar pattern which depends on the type of device in which it will be incorporated. Since these patterns are generally non-symmetrical, a considerable amount of manual adjustment of the spacer being gaged was required with prior staging devices to place the article in the proper gaging position. This, of course, considerably increased the time required for inspection. Also, the gaging of other electron discharge device parts such as anodes having a reference point on the article was extremely time consuming due to the involved manipula tion required to get the part into the desired gaging position.

Therefore, an object of this invention is to rapidly position articles for projection inspection.

Another object of this invention is to enable an operator to adjust the coarse and fine angular position of an article for inspection.

The foregoing objects are achieved in one embodiment of the invention by the provision of means for retaining an article to be gaged in an article holder and means for rotatably adjusting the angular position of the article holder about the center of the article holder.

For a better understanding of the invention, reference is madeto the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of one embodiment of the invention shown in relation to the component portions of an optical comparator;

. FIG. 2 is a front elevation view of the apparatus with FIG. 4 is a fragmentary plan view of the holder position adjusting means with some parts broken away and v sectioned.

Referring to the drawings, an article It having a perforation pat-tern'll which is to be gaged or inspected is held in the article positioning or staging fixture 12 mounted on the worktable 14 of an optical comparator. 'I'he staging device is positioned intermediate the light source 16 and the imaging apparatus 18 and is provided with article retaining means 20 on the article holder 22. Means for adjusting the angular position of the holder about the center of the holder consisting of the coarse control 24 and fine control 26 are also provided.

The fixture base 28 is'adjustably secured to the worktable 14 by bolts 30. A vertical member 32 on which the article holder 22 rotates is afiixed to the base 28 by screws 34 which pass through recesses 36 in the base.

The article holder 22 is in the form of an annulus with a portion of its periphery 38 formed as gear teeth 40. The particular size of the central aperture 42 is selected to be somewhat smaller than the diameter of the article it? which is to *be examined. While the aperture 42 of the embodiment shown is circular, other configurations may be employed which correspond with the configuration of the article to be examined. The article retainers 20 which are afiixed to the holder 22 by screws 44 are provided with a beveled end 46. The angle of the beveled edge and the thickness of the fingers 20 are such that the article may be easily inserted and removed and yet retained against the surface of the holder. The article retainers or fingers 20 may be easily replaced to accommodate articles of greater or lesser thickness which have a common outer diameter on the same holder. When the metal parts are to be examined, suitably shaped magnets may be substituted for the retaining fingers. If articles having a different outer diameter or shape are to be examined, the article holder 22 may be exchanged for another having the same peripheral size surface 38 with a central aperture 42. of the desired configuration. An opening 48 having beveled edges 59 is provided between the central aperture 42 and the peripheral surface 38 of the holder for ease and convenience of the operator in inserting and removing the article.

An opening 52 having a ledge 54 for retaining the article holder 22 is formed in the vertical member 32. The stepped portion 55 on the article holder slida bly engages the ledge 54 so that the holder may rotate in the opening 52. A recess 56 in themember 32 provides clearance for the gear teeth 4% in the holder when it is rotated to adjust its angular position. The holder is retained in the member 32 by formed spring clamps 58 which are adjustably held by screws 60 passing through slots 62 in the springs. A tail 64 formed on each of the clamps 58 rides in a groove 66 in the vertical member 32 to prevent possible rotation of the clamp about the screw 60.

A shaft 68 is rotatably supported by a bearing 70 in the vertical support 32 and a second bearing '72 in the wall 74- of the housing '76 for the fine control 26. The worm wheel 78 is affixed to the shaft intermediate the housing wall 74 and the support 32 by a pin 80. Shoulder 82 formed on the shaft mates with the bearing 70 and ex tends beyond it'within a recess 84 formed in the support 32. A pinion gear 36 is mounted on and rot-ates freely about shaft 68 and engages the gear teeth 40 formed on the periphery 38 of the holder 22. It is provided with at least a pair of radial slots 88 on its exterior surface. The knurled knob 90 is slidably mounted on the shaft 68 on bushing 92 and has projections 94 formed on one end which cooperate with the slots 88 on the gear to transmit the motion of the knob to the gear. The knurled clamp-' ing nut 96 is in engagement'with the threaded end fit! of the shaft 68. The function of this nut will be explained in detail later.

The housing 76 for the fine control gear train is afi'ixed to the base 28 by screws 1% and supports the worm gear shaft H92 in bearings 104, 106. Worm gear 108 is secured to the shaft 1&2 in a cavity 110 in the housing intermediate the bearings 104, 1% by a pin 112, in mating relation with the worm wheel 78. A knob 114 is afiixed to the end of the shaft 102 by a set screw 116 for manually rotating the shaft.

The imaging apparatus v18 comprises the viewing screen 118 and the associated optical system indicated generally at 12%. This optical system projects a greatly enlarged image or shadow 122 of the article 10 on the viewing screen. The image on theviewing screen may be meas ured with proportioning instruments or it may be compared with an enlarged drawing 124 of the desired confingers 20 and the holder 22.

figuration on a translucent overlay 126 placed in registration with the screen 118.

The staging fixture 12 is mounted on a standard vertically and horizontally adjustable worktable 14 of the optical gaging apparatus or comparator. The article to bechecked is placed by the operator on the holderZZ where it is retained between the beveled edges 46 of the In the embodiment shown in the drawings, the article lid is a circular insulating spacerh-aving a perforated pattern 11 in its major plane. Assuming that the image 122 of the article has been vertically and horizontally positioned on the viewing screen by adjustment of the worktable, the next step is to align the image on the screen so that it may be igaged by the proportioning instruments which are part of the comparator. This is accomplished by the use of the coarse and fine angular positioning means 24 and 26 respectively which cause the article holder to rotate about its center. When the fingers 2i? are properly adjusted,

the center of the article it is at the center of the holder 22, and the article will therefore .be rotated about its own center when the holder is revolved.

The coarse control 24 is used to cause the relatively rapid angular rotation of the holder 22 about its center to begin the lineup of the article image 122 with the gaging instruments on the comparator. This is accomplished by rotating the spur gear 86, which meshes with the teeth 40 formed on the periphery of the holder 22, about the shaft 68. .The gear is free to rotate on the shaft when the clampingnut is disengaged from the knurled knob 99 as shown in FIG. 4. Manual rotation of the knob90 on the shaft 68 causes the gear 86 to rotate when the profiections 94 on the knob engage the slots 88 formed in the gear face. Since the gear is not clamped against the shoulder 82 on the shaft, it is free to rotate without resistance'from the fine position means 26. If

- the gear were clamped to the shoulder 82 it would be impossible to rotate it by means of the knob 93} due to the locking elfect of the worm drive arrangement used in the fine control. 7 l

The fine control is made operative and the coarse control deactivated by clamping the gear 86 against the shoulder 82. The advance of the clamping nut 96 on the threaded portion 98 of the shaftfifi causes the bushing 92 and knob 9010 clamp the gear 86against the shoulder. I

Rotation of the shaft 102 by means of the knob 114 causes the worm gear 108 to drive' the Worm wheel 73 which is pinned to the shaft 68. This movement is transmitted to the holder 22 by the gear 86 which is clamped to the shaft. The use of the worm gear-drive allows the angular position of the holder and the article thereon to be finely adjusted due to the reduction ratio of the gear train. When the article has been thus oriented the gaging of the image 122 on the viewing screen 118 may be performed.

To increase the inspection rate, a representation of the I desired image configuration is positioned overlyingthe viewing screen 118 of the comparator. tion is laid out on translucent material so that the image on the viewing screen may be seen through the overlay 126. The operator inserts the article to be inspected in the staging fixture and by means of the fine and coarse controls causes" or attempts to cause the image of the readily apparent to the operator. i V

This representsarticle to coincide with the enlarged representation of the 1 overlay; Any discrepancy between the configuration of the --a-rticle*and the desired configuration will thus become When used with parts which are metallic, the retaining V fingers 20 may be-replaced by magnets which will retain the article on the holder during the gaging and inspecting I operation. Although the fingers are shown as symmetrically located, additional fingers in other locations may be utilized for holding non-symmetrical articles on the holder.

As previously indicated, the opening 42 in the holder is made somewhat smaller than the article to be inspected so that the article will be retained between the holder and the fingers 20. Articles of other sizes may be inspected'by exchanging the holder 22 for one having a different sized opening 42. The change in size may also be accomplished by mounting an adaptor having an opening of proper size on the holder. The adaptor is, of course, provided with retaining means 2% of its own.

Although several embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

What is claimed is:

1. in an article positioning fixture for use with an optical type comparator the combination comprising an article holder substantially in the form of an annulus, said annulus having a portion of the outer periphery thereof formed as gear teeth; .a gear meshing with the formed periphery of said annulus; first driving means selectively connectable to said gear for rotating said annulus, said first driving means including a sleeve member adapted to directly engage said gear, and means to selectively engage said sleeve and said gear; and second driving means alternatively connectable to said gear for rotating said annulus, said second driving means including a worm drive, means to engage said gear and said worm drive and means to operate said worm drive.

2. An article positioning device for use with an optical comparator comprising a frame lying in a given plane;

article holder. retaining means on said frame; an article holder substantially in the form of an annulus formed to provide an opening extending between the outer periphery of said annulus and the central aperture of said annulus with a portion of said periphery formed as gear teeth; means for retaining an article on said holder in registration with said central aperture; a first shaft supported on said frame extending transverse to the plane of said frame, said first shaft provided with a threaded end portion and with a shoulder portion adjacent said annulus; a gear meshing with said annulus periphery rotatably held on said shaft with one face of said gear adjacent said shoulder, the second face of said gear provided with a corrugated surfaceya sleeve member on said first shaft intermediate thethreaded end and said gear, said sleeve memher having the end adjacent said gear adapted to engage said gear face when forced thereagainst; a threaded member engaging said threaded end portion of said first shaft; a second gear mounted adjacent the other end of said first shaft; a second shaft lying in a plane parallel to the plane of said frame and spaced therefrom; and a worm gear mounted on said second shaft in engagement with said second gear on said first shaft whereby said first gear may be selectively driven by either said sleeve member directly or by said second shaft through said worm gear to provide movement'of said annulus.

References Cited in the file of this patent J UNITED STATES PATENTS Faber May 2, '1944 Bjong et al Aug. 27, 1957 OTHER REFERENCES 

